JP6503230B2 - Transmitted light intensity measurement unit - Google Patents

Description

  The present invention is used in a fluid concentration measuring apparatus for measuring the concentration of fluid flowing in a conduit having a light transmitting and deformable tube wall based on Lambert-Beer's law, and for transmitting light across the conduit, The present invention relates to a transmitted light intensity measurement unit that measures the intensity.

  As a pipe line having a pipe wall as described above, for example, a resin tube having a light transmitting and deformable tube wall is widely known, and a conventional fluid for measuring the concentration of fluid such as blood flowing in the resin tube As a concentration measuring device, for example, the one described in Patent Document 1 is known, and this fluid concentration measuring device comprises a light source for supplying light from the light supplying spot on the surface of the resin tube into the resin tube, The light from the light-supplying location is received at the light-receiving location located on the opposite side of the resin tube in the diameter direction with respect to the location, and the light passing through the inside of the tube wall of the resin tube and the inside of the resin tube is received And a light receiving element for outputting a signal indicating the intensity of the light.

  Further, the fluid concentration measuring apparatus is provided with optical path distance setting means for setting a plurality of optical path distances between the light supplying portion and the light receiving portion, and the light intensity at the light receiving portion at each of the plurality of optical path distances Based on the law, a plurality of relational expressions indicating the relationship between the light intensity and the blood concentration when light from the light supplying location is received at the light receiving location at each optical path distance are determined, and the relationship at the plurality of optical path distances And a fluid concentration output means for determining and outputting the concentration of blood in the resin tube from the intensity of light at the light receiving portion based on the equation.

International Publication 2014-170985

  By the way, as a result of advancing research on the above-mentioned conventional fluid concentration measuring device, the inventor found the following points. That is, in the above-mentioned conventional fluid concentration measuring device, light is transmitted between the light supplying location on the surface of the conduit and the light source or between the light receiving location on the surface of the conduit and the light receiving element in the transmitted light intensity measurement unit. Is attenuated due to scattering, etc., and the amount of light from the light source through the resin tube to the light receiving element can not be obtained sufficiently. To further improve the measurement accuracy, the transmitted light intensity measurement unit It turned out that there is room for improvement.

  Therefore, in view of the above-described point, the present invention is able to obtain a sufficient amount of light from the light source to the light receiving element by transmitting through the pipe line, and thereby the conventional transmitted light intensity measuring unit and thus the fluid concentration measuring device In order to solve the problem of

A transmitted light intensity measuring unit according to the present invention for solving the above-mentioned problems is used in a fluid concentration measuring apparatus for measuring the concentration of a fluid flowing in a pipe having a light transmitting and deformable pipe wall,
A light source for supplying light into the duct from a light delivery point on the surface of the duct;
At the light receiving point located on the opposite side of the pipe in the diameter direction with respect to the light supplying point, the light from the light supplying point is received the light passing through the fluid in the wall of the pipe and the fluid in the pipe A light receiving element that outputs a signal indicating the intensity of the light;
Optical path on between the sheet light strikes the light source and abutting said tube wall is disposed on the optical path between the light receiving portion and the light receiving element, the pipe wall by the elastic deformation of the tube wall A light transmitting member in close proximity,
The equipped,
The translucent member is characterized in convex der Rukoto having abutting convex surface on the tube wall.

  In the transmitted light intensity measurement unit according to the present invention, the light transmitting member disposed in at least one of the light path between the light source and the light supplying portion and the light path between the light receiving element and the light receiving portion Because they are in close contact, substantially no air layer intervenes between the tube wall and the light transmitting member, and minute flaws and irregularities on the surface of the tube wall are crushed at the contact portion of the light transmitting member, and the tube is The wall surface becomes smooth.

  Therefore, according to the transmitted light intensity measurement unit of the present invention, scattering or absorption of light due to the unevenness of the air layer or the surface of the tube wall between the tube wall and the light transmitting member is almost or completely eliminated. Attenuation of light due to the light source can be reduced, and a sufficient amount of light can be obtained from the light source through the conduit to the light receiving element.

Moreover, according to the transmitted light intensity measurement unit of the present invention, the translucent member, because it is a convex lens having a contact with the convex surface on the tube wall, and a translucent member focuses the light in the light transmitting member wall Light can be efficiently transmitted between them.

In the transmitted light intensity measurement unit according to the present invention, if the convex lens is a ball lens, light is focused on a portion of the light transmitting member, in particular, a portion of the light transmitting member that contacts the tube wall. It is preferable because the light can be transmitted more efficiently.

(A), (b) is the front view which shows one Embodiment of the transmitted light intensity measurement unit of this invention, and sectional drawing in alignment with the AA of (a). (A) is explanatory drawing which shows the condensing state of the ball lens in the transmitted light intensity measurement unit of the said embodiment, (b) is a collection of the hemispherical lens in other one Embodiment of the transmitted light intensity measurement unit of this invention It is an explanatory view showing a light state.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Here, FIG. 1 (a) is a front view showing an embodiment of the transmitted light intensity measurement unit according to the present invention, and FIG. 1 (b) is a cross-sectional view taken along the line A-A of FIG. 1 (a). .

  The transmitted light intensity measurement unit of this embodiment is a fluid that measures the concentration of fluid flowing in a resin tube as a conduit having a tube wall as a light transmitting and deformable tube wall based on Lambert-Beer's law. It is used in a concentration measuring device to measure the intensity of transmitted light across the conduit, and as the conduit as described above, for example, a resin tube having a light transmitting and deformable tube wall is known, and As a fluid concentration measuring device for measuring the concentration of fluid flowing in such a conduit based on Lambert-Beer's law, for example, blood flowing in a resin tube disclosed by the present applicant in Patent Document 1 earlier A fluid concentration measuring device is known which measures the concentration of H.sub.2 based on Lambert-Veil's law.

  The transmitted light intensity measurement unit of this embodiment used in the fluid concentration measurement apparatus comprises a tube holder 1 having a U-shaped notch 1a opened upward at the center in the longitudinal direction, and a notch in the tube holder 1 The light emitting unit 2 and the light receiving unit 3 provided so as to face each other across the portion 1a, and the tube holder 1 extends the resin tube 4 in the notch 1a in a direction crossing the tube holder 1 Can be held.

  The light emitting unit 2 is supplied with electricity and emits light as a light source for supplying light into the resin tube 4 from the light supplying spot S on the surface of the resin tube 4 held in the notch portion 1 a of the tube holder 1, for example The light receiving portion 3 has a light emitting element 5 such as a light emitting diode (LED) or a laser diode, and the light receiving unit 3 is a light receiving portion S at a light receiving portion R located on the opposite side of the resin tube 4 in the diameter direction. For example, it receives light passing from inside the tube wall 4a as the tube wall of the resin tube 4 and across blood in the resin tube 4 and outputs an electrical signal indicating the intensity of the light, for example, A light receiving element 6 such as a diode or a phototransistor is provided.

  The light emitting unit 2 is further disposed on the optical path between the light emitting element 5 and the light supplying spot S, and abuts the light supplying spot S of the tube wall 4a of the resin tube 4 and the tube wall 4a at the light supplying spot S The light receiving unit 3 is similarly disposed on the light path between the light receiving element 6 and the light receiving portion R and is a resin tube. The ball lens 7 as a light transmitting member is elastically recessed to be in close contact with the tube wall 4a. A ball lens 7 as a light transmitting member is in contact with the light receiving portion R of the tube wall 4a of 4 and elastically indents the tube wall 4a at the light receiving portion R to be in close contact with the tube wall 4a.

  FIG. 2A is an explanatory view showing a state of light collection of the ball lens 7 on the side of the light emitting unit 2 in the transmitted light intensity measurement unit of the above embodiment as a representative, and here approximately parallel from the light emitting element 5 not shown. The light beam L enters the inside of the ball lens 7 and is condensed to a certain extent and passes through the light supplying portion S in a narrowed state, and is supplied into the tube wall 4a of the resin tube 4 and further condensed. Then, even on the light receiving unit 3 side, the light entering the ball lens 7 from the inside of the tube wall 4 a of the resin tube 4 through the light receiving portion R is condensed to some extent within the ball lens 7 and becomes approximately parallel light To the light receiving element 6.

  And, in the transmitted light intensity measurement unit of this embodiment, it is disposed on the optical path of both the optical path between the light emitting element 5 and the light supplying point S and the optical path between the light receiving element 6 and the light receiving point R. Because the ball lens 7 is in close contact with the tube wall 4a, substantially no air layer is interposed between the tube wall 4a and the ball lens 7, and the contact portion of the ball lens 7 The minute flaws and irregularities on the surface are crushed and the tube wall surface becomes smooth.

  Therefore, according to the transmitted light intensity measurement unit of this embodiment, scattering or absorption of light due to the air layer between the tube wall 4a and the ball lens 7 or unevenness of the tube wall surface is hardly or completely eliminated. Attenuation of light due to absorption or absorption can be reduced, and the amount of light from the light emitting element 5 through the resin tube 4 to the light receiving element 6 can be sufficiently obtained.

  Moreover, according to the transmitted light intensity measurement unit of this embodiment, since the light transmitting member is a kind of ball lens 7 of a convex lens having a convex curved surface contacting the tube wall 4a, the light transmitting member, in particular, the tube wall 4a. The light can be focused on a portion of the light source S and the light receiving portion R, and the light can be more efficiently passed through the tube wall.

  In the transmitted light intensity measurement unit according to this embodiment, two ones having different distances between the ball lens 7 on the light emitting unit 2 side and the ball lens 7 on the light receiving unit 3 side, for example, FIG. As described in the specification of Patent Document 1, when used in the fluid concentration measuring device described above, the light emitted from the light emitting elements 5 in the two light emitting units 2 respectively driven by the light emitting element driver is Tube wall 4a of the one resin tube 4 compressed and deformed in the diameter direction between the light emitting unit 2 and the light receiving unit 3 of two transmitted light intensity measuring units, and the tube wall 4a near the light emitting unit 2, and the resin The blood flows through the inside of the tube 4 and the tube wall 4a on the side (opposite side) from the light emitting unit 2 (the opposite side), that is, the side closer to the light receiving unit 3 and passes through optical paths of different distances. , Respectively received by the light receiving element 6 of the two light receiving unit 3, the light receiving element 6 of the two light receiving unit 3 outputs the electrical signal of a level corresponding to the intensity of the received light, respectively.

  The output signals of the light receiving elements 6 in the two light receiving units 3 are respectively amplified by, for example, an amplifier, high frequency noise components are removed by a low pass filter, and analog signals are converted to digital signals by an analog-digital converter (A / D). It is converted and input to a central processing unit (CPU). The CPU controls the operation of the light emitting element driver to selectively cause the light emitting units 2 of the two transmitted light intensity measurement units to emit light selectively to avoid mutual interference, and the light receiving elements 6 at respective optical path distances Shows the relationship between the light intensity and the blood concentration when light from the light supplying spot S is received by the light receiving spot R at each optical path distance based on Lambert-Beer's law as known from the output signal of A plurality of relational expressions are obtained, and the concentration of blood in the resin tube 4 is obtained from the output signal of any of the light receiving elements 6 based on the relational expressions at the plurality of optical path distances, and a signal indicating the concentration data is output .

  Therefore, according to the fluid concentration measuring apparatus using the transmitted light intensity measuring unit of the embodiment described above, the light quantity of light passing from the light emitting element 5 through the resin tube 4 to the light receiving element 6 can be sufficiently obtained. The measurement accuracy of the blood concentration can be further enhanced than before.

  FIG. 2 (b) is an explanatory view showing a condensed state of a hemispherical lens in another embodiment of the transmitted light intensity measurement unit of the present invention, and in the transmitted light intensity measurement unit of this embodiment, the light emitting unit 2 and As the light transmitting member of the light receiving unit 3, the hemispherical lens 8 is used instead of the ball lens 7 in the previous embodiment, and the spherical side of the hemispherical lens 8 abuts on the light supplying spot S and the light receiving spot R The tube wall 4a is elastically recessed at the point S and the light receiving point R to be in close contact with the tube wall 4a.

  Even with the transmitted light intensity measurement unit of this embodiment, although not as large as the previous embodiment, it is possible to sufficiently obtain the light quantity of the light from the light emitting element 5 to the resin tube 4 to reach the light receiving element 6.

  As mentioned above, although demonstrated based on the example of illustration, this invention is not limited to the above-mentioned example, It can change suitably within the statement range of a claim, for example, it is as a translucent member in the above-mentioned embodiment. Although the ball lens 7 and the hemispherical lens 8 are provided in both the light emitting unit 2 and the light receiving unit 3, they may be provided only on one side, in particular, only on the light emitting unit 2 side. In that case, the light transmitting member on the light receiving unit 3 side may be in contact with the tube wall 4 a of the resin tube 4 with a flat surface.

  Further, in the fluid concentration measuring apparatus of the above example using the transmitted light intensity measuring unit of the above embodiment, the concentration of blood as a liquid is measured, but instead it may be used for measuring the concentration of other liquids. In that case, it is preferable to select light of a wavelength having a high absorptivity by the liquid as the light supplied from the light source, because the light intensity at the light receiving portion tends to differ depending on the thickness of the tube wall and the like.

  Then, in the fluid concentration measuring device of the above example, light is supplied at the light supply location at two types of optical path distances, and the light is received at the light reception location to obtain the light intensity. The light path distance may be set more than the kind, and the light intensity may be determined at each light receiving location. In this way, it is possible to further improve the measurement accuracy by averaging the obtained results.

  Thus, according to the transmitted light intensity measurement unit of the present invention, scattering or absorption of light due to the unevenness of the air layer or the surface of the tube wall between the tube wall and the light transmitting member is almost or completely eliminated. Attenuation of light can be reduced, and a sufficient amount of light can be obtained from the light source through the conduit to the light receiving element.

1 tube holder 1a notch 2 light emitting unit 3 light receiving unit 4 resin tube 4 a tube wall 5 light emitting element 6 light receiving element 7 ball lens 8 hemispherical lens L light

Claims (3)

In a transmitted light intensity measuring unit used in a fluid concentration measuring device for measuring the concentration of a fluid flowing in a conduit having a light transmitting and deformable tube wall,
A light source for supplying light into the duct from a light delivery point on the surface of the duct;
At the light receiving point located on the opposite side of the pipe in the diameter direction with respect to the light supplying point, the light from the light supplying point is received the light passing through the fluid in the wall of the pipe and the fluid in the pipe A light receiving element that outputs a signal indicating the intensity of the light;
Optical path on between the sheet light strikes the light source and abutting said tube wall is disposed on the optical path between the light receiving portion and the light receiving element, the pipe wall by the elastic deformation of the tube wall A translucent member that is in close contact with each other in a separable manner ;
The equipped,
The translucent member, the transmitted light intensity measurement unit, wherein the convex lens der Rukoto having abutting convex surface on the tube wall. The convex lens is characterized in that a ball lens, transmitted light intensity measurement unit according to claim 1, wherein. The transmission light intensity measuring unit according to claim 1 or 2 , wherein the conduit having the light transmitting and deformable tube wall is a resin tube.

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